This is not the fault of the random beach goer. This is your fault for not recognizing a potentially dangerous situation and diffusing it before it could happen.

You must presume that any and all beach goers have no clue about kites until proven otherwise. In which case you need to prepare for the worse each time you have an interaction with random people. Choose to educate the uninformed and position yourself so you do not get into that situation again.

I remember a time I was about to solo drag launch in 35 knots. A entire family of mum dad and the kids walked up and stood smack down wind of my kite with big goofy smiles on their faces wanting to watch me launch. If the high wind solo launch had gone pear shaped they would have all been taken out. I had to politely suggest to them to move upwind to a safe spot to watch.

Both have some fault. One has the ability to forsee and possibly prevent.

I like to do a little beach jump to get about 5 feet away before explaining where a beach goer can safely stand if talking to me. If they are drunk I just stay away. Usually I am going to or from the water and they are pretty sedentary so keeping up with me is not worth the effort.